Direct comparison of GaAs surface morphology between migration enhanced epitaxy and molecular beam epitaxy using in situ scanning electron microscopy

Abstract

We have used scanning electron microscopy (SEM) for real-time-observation to compare the surface evolution during the early stage growth of GaAs with molecular beam epitaxy (MBE) and migration enhanced epitaxy (MEE), at the substrate temperature of 500 °C. Surface roughness during MEE growth is about 1 ML and much smaller than during MBE growth. Immediately after growth termination, monolayer steps can be seen and the surface recovers to initial smoothness in MEE, while islands do not disappear without higher temperature annealing in MBE. Present results confirm high surface atom mobility in MEE growth.